Synthetic strategy for preparing chiral double-semicrystalline polyether block copolymers

McGrath, A. J.; Shi, W.; Rodriguez, C. G.; Kramer, E. J.; Hawker, C. J.; Lynd, N. A.
Polym. Chem.
6, 1465-1473

We report an effective strategy for the synthesis of semi-crystalline block copolyethers with well-defined architecture and stereochemistry. As an exemplary system, triblock copolymers containing either atactic (racemic) or isotactic (R or S) poly(propylene oxide) end blocks with a central poly(ethylene oxide) mid-block were prepared by anionic ring-opening procedures. Stereochemical control was achieved by an initial hydrolytic kinetic resolution of racemic terminal epoxides followed by anionic ring-opening polymerization of the enantiopure monomer feedstock. The resultant triblock copolymers were highly isotactic (meso triads [mm]% [similar] 90%) with optical microscopy, differential scanning calorimetry, wide angle X-ray scattering and small angle X-ray scattering being used to probe the impact of the isotacticity on the resultant polymer and hydrogel properties.